In recent years the game of golf has exploded in popularity, with new golf courses being built at an amazing rate. This growth in popularity has led to the introduction of golf courses into very hot, and sometimes and climates. Unfortunately, such climates are generally not conducive to the growing of certain grasses which are highly desirable for use on golf courses. While certain grasses, such as Bermuda grass, for example, have adapted to survive in such hot climates, other grasses, such as bent grass, have not.
Bent grass is highly desirable for use in golf course construction, because it provides superior speed, smoothness, and roll. Additionally, unlike some other grasses, bent grass does not become dormant in the winter. Unfortunately, because bent grass is native to areas of the country where typical daytime temperatures may be approximately 75-85 degrees fahrenheit, it does not tolerate hot, humid weather very well. Nevertheless, because of its superior properties bent grass is being increasingly used on golf courses in less than ideal climates, such as the south and western parts of the U.S, for example. This is problematic, because in many of these areas the temperature, or combination of temperature and humidity is such that bent grass cannot survive without a great deal of maintenance. This is especially true when bent grass is used in the construction of putting greens, as the greens are usually cut very short to provide a smooth putting surface, and are therefore, extremely susceptible to burning from exposure to the sun.
When bent grass is installed on a golf course in such a harsh climate, a high level of maintenance is required. If the temperature, or the combination of temperature and humidity reaches a certain level, the bent grass must be cooled to protect it from burning, especially on the putting greens. In the past, the method for cooling has generally been to water the greens to aid in convective and evaporative cooling. Unfortunately, this process generally requires a worker to run back and forth across the green with a hose in an attempt to evenly distribute water to the entire surface of the green. Because many putting greens are quite large, this can prove quite an arduous task. And, because there are usually at least 18 putting greens on a given golf course, it can be an extremely time consuming task as well. Another, more serious problem arises when using this method of cooling, however. Using water to cool a putting green often results in saturation of the grass and soil by the cooling water. The application of excess amounts of water to the bent grass on a putting green can lead to the growth of algae and disease. The more water that is applied to the green, the more likely it becomes that algae and other diseases will flourish. It is therefore desirous to provide cooling for bent grass and other grasses or vegetation susceptible to expiration by heat, without saturating the grasses or vegetation with excessive amounts of water.
The method and device of the present invention satisfies this need in more than one way. First, the device consists of a fan, which may be used to pass air over the putting green. The air movement around the green causes the grass to transpire, and thereby cool off. Additionally, water may be added to the air stream exiting the device. Nozzles may be located on the device to spray water, at various flow rates, into the air stream. The fan then helps to break up and project the water, as uniform size droplets, over and onto the green. The device may be portable or fixed in a specific location, and can utilize existing irrigation system water supplies and pressures. Nozzles of various sizes may be installed in a single device, thereby allowing the proper water flow rate for any given condition. Various motor and fan sizes may be employed to adjust the air flow rate and distance that the air/water mixture is projected from the device. Additional features may include oscillation of the device, which allows for a much larger area to be covered. The device may also be fitted with special nozzles that allow the spaying of a water mist without the use of the fan.
The device as used for cooling vegetation in the method of the present invention is unique in several ways. First, it is the only method known to the present inventors for cooling vegetation that includes a fan and water droplets to form a mist aimed at or over an area of vegetation. In a preferred embodiment of the present invention, the water droplet size is at least 50 microns across droplet width or diameter. Second, the air velocity exiting the fan and the water flow rate exiting the fan are greater than ever before used to cool vegetation or other targets. In a preferred embodiment, the air velocity is at least 50 miles per hour and the water flow rates are preferably between at least 2 and 20 gallons per minute. Third, in addition to being operable over a wide range of available water pressures, the present invention is adapted to function using typical golf course irrigation water systems of available water pressures between 60 and 125 psi. Fourth, the air stream of the present invention is preferably straight and laminar flow due to straightening vanes that may be incorporated in the present invention.
The method of the present invention is superior to traditional green watering or cooling methods in several ways. First, if the temperature is not sufficiently high, the fan of the device alone may be sufficient to cool the grass. This option saves the cost and expenditure of valuable water resources, and minimizes the chance that a green will become saturated and susceptible to algae and/or other diseases. Alternatively, if the temperature is too high to provide adequate cooling with the fan alone, an air/water mixture may be employed by injecting water into the air stream. It has been found that by tilting the device at a slight upward angle from horizontal, and projecting an air/water mixture over a putting green, virtually the entire air zone above the green may be cooled. This misting effect is able to provide significant cooling to the grass itself. More importantly, it appears that the method of the present invention is able to cool and provide moisture to the grass without saturating the soil, as the mist droplets tend to remain on the leaves of the plants. An additional benefit of this misting effect, is that the cooling and moistening of the grass may last up to one half hour longer than the effect achieved through traditional watering or cooling methods. Thus, the present invention provides a superior method and device for cooling the grass on golf course putting greens, whereby heat sensitive grasses, such as bent grass, may be used in hot, and environments, and whereby the grass may be cooled easily and without the concern for over-saturation.